Field of the Invention
The present invention relates to a recording apparatus employing an ink jet system.
Description of the Related Art
Japanese Patent Application Laid-Open. No. 2002-326347 discusses a method for discharging ink the density of which is increased in a recording head, to the outside by executing recovery operations such as a suction operation and an auxiliary discharge operation. According to the above method, because the recovery operation is executed at a predetermined time, degradation of image quality caused by an increase in density of ink can be prevented.
In recent years, an ink jet recording apparatus has been employed in order to record an image on a large-size recording sheet (recording medium). A large-volume ink tank may be used because a large volume of ink is consumed in order to record an image on a large-size recording medium. The large-volume ink tank is fixed to a predetermined position of a recording apparatus main body since it may be difficult to mount the large-volume ink tank on a carriage. Then, ink is supplied to a recording head from the ink tank through a supply tube. In a case where a recording apparatus can record an image on a larger-size recording medium such as an A1 size sheet or an A0 size sheet, the supply tube has a long length because a scanning distance of the carriage is increased.
According to the method described in Japanese Patent Application Laid-Open No. 2002-326347, in a configuration using the above-described supply tube, because the ink within the supply tube has to be discharged at a predetermined time, an amount of waste ink is increased if the supply tube is longer in length.
On the other hand, in a case where the ink is consumed by a recording operation before a predetermined time has elapsed, new ink is supplied to the supply tube from the ink tank according to the ink consumption amount, and thus an increase in density of the ink within the supply tube is moderated. Therefore, even after the above-described predetermined time has elapsed, there may be a case where density of the ink within the supply tube has not yet been increased to an extent that the discharge operation is necessary. In the above-described method, because the ink within the supply tube is also discharged under the above condition, there is a risk in which waste ink is increased more than necessary.